Telephone trunking system.



No. 885,180. I PATENTBD APR. 21, 1908.

E. H. RUPE. TELEPHONE TRUNKING SYSTEM.-

APPLIOATION FILED NOV. 15, 1906.

M WW" i i i {UNITED stratrns PATENT OFFICE.

Enwni H. RUPE, OF CHICAGO, ILLINOIS, ASSIGNOR To KELLOGG SWITCHBOARD .isUrPLY COMPANY, or CHICAGO; ILLINOIS, 'A CORPORATION OF ILLINOIS.

TELEPHONE TRUNKING SYSTEM.

Specification of Letters Patent.

' Patented April 21, 19 O8.

Application filed November 15, 1906. Serial No. 343,540.

..cago, county of Cook, and State of Illinois,

have invented certain new anduseful Improvements in Telephone Trunking Systems, .of which the following is a specification.

My invention relates to improvements in tele hone trunking systems. employed in es ,tabishing conversational connection between toll andcoinmon battery lines. It is usual for toll lines to terminate before toll 0 erators at a .main or central exchange, t ese operators being provided with connectthey are enabled to connect the different toll lines together for conversation; It often occurs, however, that local subscribers'whose lines terminateiat otherexchanges are desired,a'.nd inorder to connect with these sub- "scribers a trunk circuit extending from this main ortoll board to an auxiliary exchange is used to further the connection.

:My invention contemplates 'the simplifying of the apparatus necessary in furtheringthI S' COIIDGClJlOIISthI'OII h the trunk line,.an

- entirely shown-in its normal or unactuate particularly in means or placing the connection of ringing current with the desired line under the control of the toll operatorj Other objects of the invention will be hereinafter described and claimed, reference be-- inghad to the .ac'com anying drawing formmay be multiplied before a number of operators positions. The si nal 3 is adapted tobe actuated over the.to l-line which may terminate before another toll operator at a i distant; station orin a .local batterystation asshown. r

- The toll operator is provided with a plu- :rality of connectingjcircuits such as the one ashown at 4, each circuit being provided with a an answering plug 5 and calling plug 6. The tip contacts of the plugs are normally contalking purposes by the strand 8, the con-' nected for talking purposes by the strand 7, while the ring contacts are connected for densers 9 and 10 being placed in each strand ing circuits known as. toll cords by which source will be maintained actuated.

sleeve contact of the calling ing circuit-of relay 17, the

and listeningrey for the purpose of conductively separating the two ends of the connecting circuit in or der to furnish double su )ervision for the toll operator. A-relay 11, having a high resistance and impedance coil 12,.is bridged across the answering end of the cord circuit and is adapted to control the circuit of signal 13 which is associated with that end of the connector. A locking coil 14 is also rovided on relay 11 so that the sigiialwhen isplayed by currents from ,a temporary or intermittegit T is looking circuit is controlled by 'contacts of relay 15 which is actuated from the source 16 over the sleeve of the answering plug 5 whenever a connection is established with a toll line. The calling endof the toll con nector is similarly provided with relay 17 having a similarly connected high impedance coil 18, and locking coil 19, signal 20 bein controlled by the actuation of relay 17. The relay 21 has its coilconnected with the plug and has, in addition to thecontact controlling the locktacts 22' controlling the circuit of the ringing current. The calling end of this toll connector is also )rovided with the usual ringing i 23, the operators set 24 be ing adapted to be connected with any one of the toll connecting circuits under the control of this articular toll operator.

Thet ree-point jack 25 which may be multiplied before a number of toll operators has its tip and ring contacts connected with the strands 26 and 27 of the trunk line, While its sleeve contact is normally free from any connection.

In the auxiliary exchange the limbs 26 and 27 are connected with the windings 28 and 29 of the repeating coil 30, the inner terminal of winding 28 being normally connected with ground by way of conductor 31, normal contacts 32 of relay 33, conductor 34 and the 0Q1l of relay 35,-while the inner terminal of coil 29 extends to the normally open contact of relay 33 where it is adapted to be connected with conductor 31 by the actuation of relay 33. From the point 36 on conductor 27 just outside the winding 29 the conductor 37 extends to the live pole of battery 38 by way of the normal contacts 39 of relay 33, the coil of relay 40 and conductors 41, 42 and normallyopen conends permanently connected with the tip, and

sleeve talking conductors 47 and 48 which during conversation connect with contacts of the plug 49. Bridged between the live pole of battery 38 and conductor 48 is the coil of relay 50. The contacts of this relay and of relay 40 together control the local cireuitconta-ining signal'5l, the armature of relay 40 being normally connected with conductor '52 which is normally broken at the" while the grounded armature of relay 50'is normally connected with conductor 53 which is normally broken by the contacts of relay 40. The coil of armature of relay 50,

I relay 54 is connected between the ground pole of battery 38 and talking conductor. 47, contacts of this relay controlling the circuit of relay 33 through conductors 55 and 56, 41, 42 and 431 The relay 57 has one of its terminals connected with the live pole of battery 38 and its other terminal connected through conductor 58,-the normally closed contacts 59 and 60 of relays and 33 to the normally open contact 61 of relay 40, the armature of relay being connected with the ground pole of battery 3 8. The armature 62 of ,relay 57 is normally connected with cond uetor vi=7 but is adapted to be connected with any desirable source. of ringing current through its normally open contact, while the armature 63 is adapted by its actuation to connect the sleeve strand of the talking. circuit with the live pole of battery 38 through the non-inductive resistance 64.-

provide an automatically dis-- In order to connected testing circuit the tip of the plug is normally connected by conductor 65 through contacts of relay 50 and conductor 66 to the tertiary of the o erators'induction coil 67, the actuation of re ay 50 being adapted to disconnect the tertiary of the induction 'coil 67 and to connect the conductor 65 with conductor 68 which is a portion of the tip strand of the talking circuit.

The operators listening set which comprises the usual receiver 69, induction coil 67, condenser 70 and transmitter 71 is connected through order wires with the toll operat-ors set and may be used with a' plurality of trunks such :is the one shown in the'drawmg.

The plug 49 is adapted to connect with any one of a plurality of common battery telephonelinvs, one of which is here shown terminating at the central ofiice in spring jack 72 and extending in limbs 73 and 74 to the hate central office the line relay 80 is normally connected with the limb 7 4 of the telephone line and controls the local circuit of signal 81, while the; limb 73 is normally grounded. The cut-off relay S4 is ,ada )ted to be actuated over a portion of the talking circuit to disconnect the line signaling apparatus and ground from the limbs 7.4and 73 and to connect the tip and sleeve contacts of the jack 72 directly with the line. I

In the operationof this system the call is sent in over the toll line 1 and the signal 3 is displayed before the toll operator. Upon observing this signal the plug 5 is inserted in the jack 2 thus completing a circuit from battery 16 over the sleeve of the pin 5 which actuates the relay 15 and the cut-o relay of the calling toll line. The actuation of relay 15 places the lockin circuit 0t relay 11 in condition tobe closer? by the actuation of the latter relay. The toll operator now throws her listening key and obtains the number of the desired subscriber. Finding that the desired subscribers line terminates before a certain trunk o )erator th toll operator presses the order utton'whibh connects her own operators set directly with the set of the operator before whom the desired line terminates. The toll operator then orders the connection and the trunk operator desi nates which of hertrunks she Wlll use. Picfiing 11 the plug of the trunk-she has desigthe trunk o erator tests the desired line to ascertain w ether or not it'is in --use.' If the line is busy the sleeve of the jack will be at a potential higher than that of ground and.a current will flow over the tip of the plug through conductors 65' and 66 and the causing a click which notifies the operator that the line-is busy. I v

Assuming the lineto be idle the trunk operator inserts the plug 49 into the jack 72 thus closing a local'circu'it from the battery 38 through the'coil of relay 50'over the sleeve strand of the trunk and throu hthe of cut-elf relay 84 to ground. his actuates relay 84 to place the desired line in condition to be called, and relay 50 to close the-circuit of signal 51 through the normal contact of relay 40 and conductor 52. This testing and connecting with the desired line requires a little time on the part of the trunk operator. and it is supposed that in the meantime the toll operator will have inserted her calling plug 6 in the designated trunk line whichterminates at her board in the jack 25. Upon the connection of the toll cord with the outgoing end of the trunk a circuit is completed which may be traced from the live pole of battery 33 through conductors 43, 42 and 41, the 0011 'tertiary of the operators induction coil 67, r

of relay 40,contacts 39 of relay 33,conductor guardsignalto'indicate to the trunlg ,operof supervisoryrelay 17,' ti st'rand7, thetip contacts of plug 6 and ac 2.5,, conductor 26, the winding 286i repeating coil 30, conductors 31 and 3.4 and through the coil .35 to the ground pole of battery 38.

'.The relays '17, 35jand40 in the path just traced, each being' of high resistance, will be actuated," the actuation of' relay 40 serving -to ,efface thesignal'51 if ithas-been pre- 'vious ly displayed'by the actuation of relay 50," .or-to "display said signal by current'over conductor .53- and' the normal contacts of rela 50 if the latter has not yet been actu- 'since when the l plug {6 is connect'e ate by'the insertion of'the calling "plug 49. Itis'seen that the signal 51thus acts as a ator thatlthe toll operator is' connected with the proper trunk line, the signal being effaced as soon as connection exists at both ends of .20 V .toll connector, now being actuated the signal j is displayed. The 'toll' operator now throws-her ringing key 23 placing ground the trunk. Relay 17,associated with the on the'ring side of the'toll line but 'not p acing ringing current upon the tig' side,

\ a" trunk -.line having the sleeve contact ("disconnected no current 'will flow from. 'ibattery 16'through" the relay '2 1,-and con- 3 I to place' rin ing current upon the normally disconnecte Ground being-placed upon the ringside of sequently contacts .22 will "not be'closd contact of the ,ringing key.

the calling end of the *toll'connector and the normal circuit bein broken in the tip side'of the toll cord, 'the re ay '35 which was actuated Cover the outgoingfend offthe'trunk will now be deprived of current and-its armature will fallback to complete the local circuit of relay ,5 7;, relay 40 being maintained actuated by current from the live ole of battery 38 over conductors 43, 42 an 41, its own coil, conductors 37 and 27 and the ring contactsof jack- 25 and plug 6 to ground through the contact of the ringing key 23.. By the actuation of relay=57 signaling current is conet e with the tip side of the line through the armature 62 'while battery is connected with the sleeve side of the line through the nonnductive resistance 64 and the armature 63. The ringing current thus sent u )on' the line passes through conductors 68 an 65 and out over the tip side of the line actuating the annunciator 75 and returning rover-the line conductor 74 to the generator through 1' the-non-inductive resistance 64 and the battery 38. This non-inductive resistance 64 --is so adjusted in resistance that it will not i shunt the relay sufficiently to allow it tofall 1 back but-'will' offer-a patlf for the returning ringing current of sufiiciently low impedance to prevent the demagnetization or rattling of eit i er relays 84 or 50.' It will be noted that if the toll operator should throw her ringing.

with

I key beforeth'etrunk o erator had insertedher calling plug, that w ile the relay 57 will be actuater under these conditions, no ringing current will he placed on the contacts of the plug due-to the fact that the tip strandis normally open at contacts of relay 50.

-When the called subscriber answers his .call a path for current from battery 38 is completedthrough the coil of relay 50, the sleeve strand of the called line, t e called subscribers switch-hook and back to the ground pole of battery 38 actuating the relay 54, transmitter current thus being fed to the common battery line through the coils of relays 50'and 54. The actuation of relay 54 closes the local circuit of 'relay 33, the actuation of which serves to short-circuit the inner terminals of windings 28 and 2.9 of induction coil 30 and to disconnect the coils of both relays 35 and 40 from the outgo ng end of the trunk line, thus severing connection for ourrent from battery 38 over the outgoing end of the trunk and depriving relay 17, associated with the toll cord, of actuating current, whereby the signal 20 will 'now be eiia'ced to indicate to the toll-o erator-that the desired party hasxansw ered iiiscallf.

*The actuat'on-of relay- 33 deprives relay 35 of actuating current, and sit the sametime dition,vthe signals before both operators bemg efiaced. 'lhe disconnect signal may now be sent in,either from the common battery station or over the toll line. When the dis-- connect signal is sent in over the toll line the current which is usually alternating or intermittent passes through t-hehigh resistance 1 coll of re ay ll actuating that relay to close the local circuit of the signal 13, and at the same time, to close the locking circuit through its own coil 14. When the common battery subscriber replaces his receiver upon the hook the relay 54 will be deprived of actuating current and will fallback opening the circuit of relay 33, the denerglzation of which again connects the poles of the-battery with the limbs Ofxbile outgoing end of the trunk through the coils ofrelays 35 and 40 and consequently'through the coil 18 of the bridged relaylT- associated with the toll cord:

The actuation ofwthis relay closes the local circuit ofsignal .20,displaying it to indicate 'to the toll operator that the conyersation has terminated. Wh'en both signals 13 and 20 are thus .displa edv the toll operator removes' the plugs 5 anti 6 from their respective jacks a's a be connected, and means de ending upon the 45 said key, and j acks of diilerent character with which the' cord may be connected substanand her apparatus immediately assumes its normal unactuated condition. The removal of the plug 6 from the jack 25 severs the circuit of relays'35 and 40 allowing them both to fall back. The deener ization of the relay 40 displa *s the signa 51 through conductor 52 an the contact of the now actuated relay 50. Upon observing this signal the trunk operator removes her plug 49 from its connection with the called line thus severing the circuit of relay 50, e-flacing the signal 51 and allowing all of her apparatus to as sume its normal unactuated condition.

, While I have thus described my improvements in connection with a specific telephone system I do not wish to so limit the scope of my invention, certain features of which-may be applied to many different specific arrangements.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is: 1. In a telephone system, the combination with a cord circuit, of 'a ringing key associated with the cord circuit, a'plurality of jacks of different character with which the cord may be connected, and means depending upon the character of the jack with which the cord circuit is conn cted for governing the connection with said key, substantially as described-J 2.. In a telephone sv stem; the combination with-a cord circuit, 0 a source of ringin current, a ringing key, a plurality of jacI s of different; character with which the cord may character of the jack with w ich the cord circuit is connected for governing the connection of the rin ng current source with the ringing key, su stantially as described.

3. In a telephone system, the combination with a cord circuit, of a ringing ke and a relay, the actuation of which depen s upon thecharacter of the jack with which the cord is connected, for governing the connection with tially as described.

4.- In a telephone s stem, the combination with a cord circuit, &( apted to connect either with a subscribers line or a trunk line, of a sourceof ringing current, a ringing key, and a relay controlling the connection of said source with said key, the actuation of said rela depending upon the character of line with w ich the cord IS connected, substantially as described.

' 5. In a telephone system, the combination with a cord circuit, of jacks of different character with which the 'cord may be connected, a source of ringing current, a ringing key, a

relay for controlling the connection of the ringing current with the key, and means depending upon the character of the jack with which the cord circuit is connected for controlling said relay, substantially as de scribed.

6. In a telephone system, theconibinat'ion 5 the third contact of the connecting plug, .a

plurality of jacks having differently connected sleeve contacts with which said connectin plug may be connected, the actuation oi said relay depending upon the connection of the sleeve contact of said jacks, substantial! as described.

7. In a te ephone system, the combination with a telephone line, of a cord circuit to connect therewith for conversation, a source of ringin current for the cord circuit, a ringing key a apted when actuated to connect sai source with said line when the calling end of the cord circuit is connected therewith, a

trunk line with which the calling end of said cord may also be connected, and means to revent said source from'being connected with the trunk line when the calling end of the cord is connected therewith and the keyis actuated, substantially as described.

8. In a telephone system, the combination with a trunk circuit, of a cord circuit adapted to be connected with the outgoing end, and a connecting circuit permanently connected with the incoming end thereof, a source of direct current and a relay associated with .the incoming end of thetrunk circuit, a source of ringing current adapted to be connected with the incoming end of the trunk circuit by the actuation of said-relay, and means to actuate said relay by current from said direct current source upon the actuation of said ringing key, substantially as described.

9. In a telephone system, the combination with a trunk ine and a subscribers line, of a cord circuit adapted to connect with either, a

ringing current source, a ringin key, and means whereby said source wil be' connected with the subscribers line when the callin end of the cord is connected therewith and te keyis actuated, andwhereby said source will not be connected with the trunk line when the calling end of the cord is connected therewith and the key is actuated, substantially as described.

1'0.' In a tele hone system, the combination with a trlin line and a subscriber's line, of a cord circuit adapted to connect'with either, a ringing current source adapted to be connected with the subscribers line for calling purposes when the calling end of the cord --tion with a trunk line, of -a cord circuit nd thereof, and a lelcplume line with which end thereof, and a telephone line with whic actuated by the energization of said first reis connected therewith, and means whereby said source cannot be connected with thel trunk line when the calling end of said cord is connected with the trunk line, substantially as described.

11. In a telephone system, the combination with a trunk line, of a cord circuit-- adapted to be connected therewith at its outgoing end, and a telephone line with which its incoming end is adapted to be connected, a source of direct current associated with the incoming end of the trunk, a ringin relay having its coil connected with sai source, a ringing key associated with the cord; circuit, aneans o erative uponthe actuatipn" of such ringing 'ey for closing the circuit of said source through the ringing relay, means actuated upon the connection of the incoming end of the trunk with the telephone line for placing rin ing current upon the tele-' phone line, an means operative upon the response of the. called subscriber for deenergizing the ringing relay, substantially as described;

12. In a telephone system, the combination with a trunk line, of a cord circuit adapted to be connected with the outgoing the incoming end may beconnected, a source of direct current associated with the incoming end of the trunk, a relay having its coil normally connected between such source and the outgoing end of the trunk, a ringing key associated with the cord circuit, the actuation of which corn letes the circuit of said source through sai relay, :1 source of ringing current, a ringing relay, and means lay for actuating. the ringing relay to place ringing current upon the incoming end of the trunk, substantially as described.

' 13. In a telephone system, the. combine tion with a trunk line, of a .cord circuit adaptedito be connected with the outgoing end thereof, and a tele hone line with which the incoming end may. e connected, a source of direct current associated with the incoming end of the trunk, a relay: having its coil normally connected between such source and the outgoing end of the trunk, a ringing key associated with the cord circuit and adapted by its actuation to complete the circuit of said source through said relay, a source of ringing current, a ringing relay for connecting said ringing source with the incoming end of the trunk having its circuit controlled by the contacts of said first relay, and means for severing the circuit of said ringing relay upon the response of the called sul')scribcr, sub stan-tially as described.

14. In a telephone system, the combina- -the sleeve contact of said jack adapted to be connected with the outgoing the incoming end may be connecteia source of direct current associated with the'incom ing end of the trunk, aQ'elay having its coil normally connected between suchsqurce and the outgoing end ofthe trunk, a rin'gmgjkey associated withthe cord circuit and ada "ted,

the responseof'f'the called subscriber, substantial y as described. 15. In a telephone system, the combination with a trunk line, of a cord circuit adapted to 'be'connected with the outgoin end thereof, anda telephone line with'whic source of direct current .associated with the incoming end of the trunk, a relay having its coil normally connected between such source and the outgoing end of the trunk, a ringing key associatedwi-th the cord circuit adapte by its actuation to complete the circuit of said "source through. said relay, a. source of current, a ringing relay for connect- .the incoming en d may be connected, a

mg sa1d"nng1ngsource' with the incoming I end of the trunk having its circuit controlled bythe contacts of said first relav, and means for disconnecting said first 'reIay from the 'outgoing end; of the trunk upon the res use of the called subscriber, substantialyas described.

16.'Ii1.a telephone syste' inrthe combination with a trunk line, of a cord circuit adapted to be connected with its outgoingend, and a telephone line with which its incoming end may be connected, a three-point jack forming a terminal at the out oing and,

beingnormally disconnected, 4 a ringing key associated with the cord circuit, and adapted by its actuation ,to place ringing current upon a telephone linewhen the sleeve contact of the line jack is properly connected, means operative when the cord circuit is connected with the trunk 'ack for preventing ringing current from sing connected with the trunk line. by the actuation of the ringing key, and a circuit completed by the actuation of said ringing key for causing ringing current to be )laccd upon the incoming end of the trunk line, substantially as described.

17. In a telc )honc system, the combination with a trun k line and a subscribers line.

at l

of a cord circuit, the calling end of which is adapted to connect with either of said lines, a ringing key, a source of ringing current adapted to be connected w th the calhn end of said cord circuit by the actuation 0 said key when the calling end of the cord is conncctcd with sald subscrxb'ers'hne, and means wherebysaid ringing current source will not be connected vmh the 0 911111 end of sand 1 wltnesses. cord by the actnatlon of, Sana rmgmg key k when the callm end 0t sald cord 1s connected 5 with the (run line, substantiall as de- 1 t and State of Illin0is,-in the presence of two EDWIN ,H. RUPE.

Witnesses CLIFFORD C. BRADBUUY,

EDITH F. GRLERL scribed. 1 Sxgngd by me at Clncago, county 0t Cook, 1 

